Switch actuating mechanism with overtravel transmitting motion means



United States Patent SWITCH ACTUATING MECHANISM WITH OVER- TRAVEL TRANSMITTING MOTION MEANS Theodore Y. Korsgren, Jr., Woodbury, and Neal M.

Lavado, Waterbury, Conn., assignors to Tri-Tech, Inc.,

a corporation of Connecticut Filed Dec. '13, 1962, Ser. No. 244,371 16 Claims. (0]. 200-7) This invention relates to mechanical rotary actuating mechanisms and, more specifically, to a new and improved bidirectional, over-travelling, self-centering, hermetically sealed switch and actuator combination.

The switch combination of the present invention is especially advantageous in applications where multiple, bidirectional switching operations are required to be made in extremely short periods of time, for example, in the control of the flight systems of a large jet propelled aircraft. Specifically, the switch actuating mechanism of the present invention includes a pair of torsion springs which function rapidly and efficiently, upon the application of a rotary actuating force, to accommodate immediate and positive, completely safe switch actuation through predetermined actuator over-travel allowances and to return the switch actuating mechanism automatically to a neutral or central position upon release of the actuating force.

More specifically, the advantageous switch actuation of the device of the present invention is accomplished through the cooperation of the torsion springs with four collarlike elements, two of which are fixed to and rotatable with an actuation shaft, one of which is fixed to a housing and non-rotatable, and one of which is not fixed and is rotatable independently of the shaft. The collarlike elements, the springs, and the actuation shaft are assembled in a new and improved combination to provide twin operating systems, which center the mechanism upon removal of an actuating displacement and accommodate substantial actuation shaft over-travel when an excessive actuating movement is present.

The centering system of the invention restores the actuation shaft from an angularly displaced, switch-opcrating position to a centered, inoperative position, by means of a centering torsion spring acting against a centering collar, which is fixed to and rotatable with the actuation shaft and acts against a reference collar fixed to the housing. The action of the spring is constantly to urge the centering collar into alignment with the reference collar. 7

The over-travel system incorporated in the device of the invention accommodates over-travel of the actuating shaft in either of two directions beyond predetermined switch actuation points by means of an over-travel collar which is fixed to and rotatable with the shaft. Associated with the over-travel collar is an over-travel spring of sulficient rigidity to transmit rotary shaft motion to a freely rotatable actuating collar. Upon the full actuation of a switch element by the actuating collar, its further travel is restrained; however, the over-travel collar may freely continue to rotate. The lost motion of the continued rotation of the over-travel collar beyond the actuation point is taken up by the over-travel spring, which acts between the over-travel collar and actuating collar.

For a more complete understanding of the nature of the present invention and for further specific advantages to be obtained therefrom, reference should be had to the accompanying drawing, in which:

FIG. 1 is a front elevational view, with certain parts shown in section, of a bidirectional switching mechanism made in accordance with the principles of the present invention, with the actuation shaft slightly displaced in ice a counterclockwise direction, and with parts of the hous-" ing broken away to show the over-travel system in a neutral or inactive position;

FIG. 2 is a cross-sectional view of the mechanism of FIG. 1 taken along line 2-2 thereof;

FIG. 3 is a front elevational view of the switch actuating mechanism of FIG. 1 in one of its operative, overtraveled positions with parts broken away and in section to show details of the over-travel system; and

FIG. 4 is a cross-sectional view of the mechanism of FIG. 2, taken along line 4-4 thereof, showing the details of the automatic, self-centering system in its neutral, centered position.

With reference to FIG. 1, it may be seen that the entire switch actuating combination is enclosed by a housing 10. In the specific, illustrated device, two pairs of switches 11a and 1117, having spring biased, depressible plungers 12a and 12b, are rigidly mounted to an A shaped plate 17 within the housing 10 by a plurality of rivets 14. The plungers 12a, 12b advantageously are disposed in a colinear, opposing relation and are adapted to be selectively actuated by a bifurcated switch blade 15 freely rotatably mounted about an auxiliary shaft 16, which is journaled by the A plate 17 and a housing wall 18 (FIG. 2).

In the detailed description to follow, the operation of the switch combination will be described in terms of actuating the switches 11a. It is to be understood, however, that the structure of the mechanism of the present invention is substantially symmetrical, and most advantageously its operation is bidirectional. Thus for the sake of brevity and clarity, for the most part the components which cooperate to actuate switches 11a will be given a reference numeral with postscript a, while their symmetrical counterparts which actuate switches 11b will be given the same reference numeral with the postscript b. It will be seen that application of a rotative force to a crank 27 in a clockwise direction will result in the actuation of switches 11a through the cooperation of the a elements, while, conversely, application of a counterclockwise force will result in the actuation of switches 11b through the cooperation of the b elements.

In the absence of an applied actuating force, the switch blade 15 is maintained in a central, inoperative position by the counteraction of the plungers 12a, 12b. As may clearly be seen in FIG. 3, counterclockwise movement of the switch blade 15 about its axis will cause the lower portion of the blade to travel to the right and depress the plungers 12a to actuate the switches 11a. Conversely, clockwise movement of the blade will cause the actuation of the opposed switches 11b.

In accordance with one aspect of the invention, the blade 15 may be moved into either of its two active positions by a rotatable actuating collar 19 provided with a pair of arms 20a, 20b advantageously having adjustable contact screws 20 and 21, respectively. As best seen in FIG. 2, the actuating collar 19 advantageously includes a flange 22 and a cylindrical body portion 23 and is rotatably mounted on a main actuating shaft 24, which shaft is rotatably mounted by a bearing insert 25 and by a bearing surface 26 of the housing 10. The main shaft, which projects from the housing, may be given rotational movement in a clockwise or counterclockwise direction by application of an actuating force to the crank handle 27, which is attached to the outer free end of the shaft. Advantageously, the crank is of substantial length in comparison to'the other elements of the mechanism to obtain a relatively large mechanical advantage and assure positive switch actuation with minimum applied forces.

The actuating collar 19 has an axially projecting arcuate portion 28, having a predetermined central angle of an axially projecting arcuate portion 32 having substantially the same central angle (i.e., about 120) as the actuating collar arcuate portion 28. The free ends of the arcuate portion of the actuating collar are designated by reference numerals 28a, 28b (FIG. 3), while the corresponding free ends of the over-travel collar arcuate portion are designated by numerals 32a, 32b, for the sake of clarity in the ensuing functional description.

The actuating collar 19 andthe over-travel collar 29 are mounted coaxially on the main shaft 24 with the outside diameters of their respective body portions being coextensive, as best seen in FIG. 2, to receive an overtravel assembly sleeve 33 thereover. An over-travel torsion spring 34 having radially projecting free ends 34a, 34b is mounted over the collar bodies 23, 31. The ends 34a, 34b are arranged in position to engage each of the free ends 28a, 28b, 32a, 32b of the axially projecting arcuate portions 28, 32 when both the collar 19 and the collar 29 are aligned while the mechanism is in the neutral or inactive position, as is best illustrated in FIG. 1. In this neutral or inactive condition, the over-travel torsion spring 34 is under a predetermined torsion stress; that is, it tends to align the arc portions 28, 32 of the actuating and over-travel collars substantially as indicated in FIG. 1.

The over-travel system herein above described functions as follows: The crank 27 may be moved by an actuating force in a clockwise direction to impart similar rotary motion to the main shaft 24. The over-travel collar 29, affixed to the main shaft, also will be rotated in a clockwise direction and will transmit its rotation to the actuating collar 19 through the cooperation of the over-travel torsion spring 34 and collar arcuate portion 28a as a result of the initial torsion stress of the spring 34, which is sufficient to overcome the resistance to rotation of the actuating collar 19. Continued rotation of the over-travel collar will cause the contact screw 20 on the arm 20a to engage the switch blade 15 and to rotate it in a counterclockwise direction about the auxiliary shaft to actuate switches 11a through the depression of the plungers 12a. The free travel of the blade 15 will be limited by the travel limits of the plungers 12a, and, once halted, the blade itself will block continued clockwise rotation of the arm 20a and the actuating collar 19. At this point in the sequence of operation of the mechanism, the over-travel system will take effect and protect the switch and actuating assemblies from possible harm from the application of an excessive actuating force.

Continued clockwise crank rotation, beyond the limit point of actuation, will result in the arcuate collar portion 32 continuing its travel against the increasing resistance of and with the accommodation of torsional displacement of the torsion spring 34, while the arm 20a remains stationary at the actuation limit point, as clearly shown in FIG. 3. The over-travel of the collar 29 will continue until it is limited by a projection in its path, namely, a stopping lug 35a, which is advantageously aflixed to the A frame 17, in position to cooperate with the free end 32a of the arcuate portion 32 to limit overtravel of the collar 29 in the clockwise direction A corresponding lug 35b performs the same function for overtravel in the opposite direction. As will be understood, the stopping lugs are so positioned, in relation to the strength and initial tensions in the torsion spring 34, as to positively stop the over-travel collar 29 at a point before excessive force is applied through the spring to the actuating collar 19; at the same time, the assembly accommodates a desired substantial rotary over-travel of the main shaft 24, as may be required for compatibility with an external actuating mechanism (not shown).

The automatic self-centering system of the mechanism of the invention operates and is constructed in a similar manner to that of the over-travel system. A cylindrical reference collar 36 with a projecting axial arcuate portion 37, having free ends 37a, 37b, is affixed along its outside diameter to the housing and supports the shaft bearing 25 along its inside diameter.

A centering collar 38, somewhat similar in shape and operation of the over-travel collar 29, is fixedly mounted on the main shaft 24 by a collar pin 39. The centering collar 38 includes an axially projecting arcuate portion 40 extending for approximately and having free ends 40a, 4011 which engage radially projecting free ends 41a, 41b of a centering torsion spring 41. As shown in the drawing, the centering spring 41 is similar in shape and operation to the over-travel torsion spring 34, although being effectively stronger. The centering spring 41, like the over-travel spring 34, has a predetermined initial tension such that a positive and substantial restoring or centering force is available in any rotary position of the shaft 24.

The described arrangement is such that the free ends 41a, 41b of the centering spring engage the edges 37a, 37b of the reference collar 36, when actuating forces are absent, to maintain the shaft in the central or neutral position through alignment of the centering collar free ends 40a, 40b with the reference collar edge portions 37a, 37 b. When the crank 27 is rotated in the clockwise direction, the end 410 of the spring will be moved away from the edge 37a :by the free end 40a of the centering collar 38, while the free end 4112 of the spring will remain engaged with the free edge 37b of the arcuate portion 37. The action of the spring 41 is to urge the collar 38 back toward its central position in alignment with the collar 36 whenever it is rotated away from that position. Thus, relaxation or release of the switch actuating force from the crank handle 27 will result in the shaft being snapped back into the central position.

As shown in FIG. 2, a flanged assembly sleeve 42, similar to the sleeve 33, is provided to support the centering spring 41 between a flexible, longitudinal sealing sleeve 43 and the arcuate portion 40.

Lead Wires 44 to the switches 11a, 11b are permanently sealed in a potted sleeve 45, and the housing is welded at 46-48 to be substantially airtight. The sole source of potential leakage into the housing is the area around the shaft at the inner bearing surfaces. Elimination of that potential leakage and thus complete hermetic sealing of the housing from the surrounding atmosphere advantageously may be accomplished through the use of the resilient, longitudinally disposed, sleevelike sealing element 43, which is bonded at one end to the reference collar 36 and at the other end to the main shaft 24, in an annular recess 49 thereof. The sealing element 43 effectively seals the area around the shaft and assures that the entire mechanism is fluidtight.

From the foregoing description and from the illustrated embodiments, it will be apparent to those skilled in the art that the switch combination of the present invention affords a new and improved mechanism for positively, efficiently, and safely actuating in either of two directions a switch or a plurality of switches through an applied rotary actuating force. The switch mechanism of the invention is usable to particular advantage in applications where a large actuating motion is necessary or desirable, as Where the switch is actuated through a related mechanism having a variable actuating motion or, for some reason, requiring an actuating motion substantially in excess of that required to actuate the switches 11a, 11b. The mechanism of the invention, while accommodating substantial over-travel of the main actuating shaft, and while providing for automatic recentering of the shaft, is of a particularly compact and reliable construction, suitable, for example, for use under the strenuous and rigid requirements of military aircraft and the like.

Many of the advantages of the new and improved switch combination are realized through the unique twin spring systems, both of which are operative bidirectionally. The centering spring system functions to restore the mechanism to a neutral position whenever an actutaing force is removed, while the over-travel system functions to accommodate excessive actuating motion.

While the present invention has been described in respect to a specific preferred embodiment by way of illustration only, the scope of the invention is to be limited as set forth hereinafter in the appended claims.

We claim:

1. In a switch actuating mechanism, in combination, a control shaft rotatable from a neutral postion to and beyond a switch actuating position, centering means cooperating with said control shaft for resiliently biasing the same toward said neutral position, a switch actuating element movable with respect to said shaft, and over-travel means including a torsion spring disposed about said shaft and having two end portions for transmitting motion between said shaft and said switch actuating element, one of said end portions being movable with said shaft and the other of said end portions controlling said switch actuating element, rotary movement of said shaft from said neutral position beyond said switch actuating position being resisted by said torsion spring.

2. In a switch actuating mechanism, in combination, a control shaft rotatable in a clockwise direction from a neutral position to and beyond a first switch actuating position and in a counterclockwise direction from said neutral position to and beyond a second switch actuating position, centering means cooperating with said control shaft for resiliently biasing the same toward said neutral position, a switch actuating element movable with respect to said shaft, and over-travel means including a torsion spring disposed about said shaft and having two end portions for transmitting motion between said shaft and said switch actuating element, one of said end portions being movable with said shaft and the other of said end portions controlling said switch actuating element, rotary movement of said shaft from said neutral position beyond said switch actuating positions being resisted by said torsion spring.

3. In a switch actuating mechanism, in combination, a control shaft rotatable in a clockwise direction from a neutral position to and beyond a first switch actuating position and in a counterclockwise direction from said neutral position to and beyond a second switch actuating position, means including an actuating collar carried by said shaft for rotary movement with respect thereto, an over-travel collar affixed to said shaft, and means for transmitting motion between said over-travel collar and said actuating collar, said last-mentioned means including a torsion spring disposed about said shaft and having two end portions cooperating with said collars, rotary movement of said shaft from said neutral position to said actuating positions producing corresponding movement of said over-travel collar, said torsion spring and said actuating collar, and rotary movement of said shaft beyond said actuating positions producing relative movement between said over-travel collar and said actuating collar against the resistance'of said torsion spring.

4-. In a switch actuating mechanism, in combination, a control shaft rotatable in a clockwise direction from a neutral position to and beyond a first switch actuating position and in a counterclockwise direction from said neutra-l position to and beyond a second switch actuating position, means including an actuating collar 'rotatably carried by said shaft and having a first longitudinally extending arcuate portion, an over-travel collar affixed to said shaft and having a second longitudinally extending arcuate portion, and means for transmitting motion between said over-travel collar and said actuating collar, said last-mentioned means including a torsion spring disposed about said shaft and having two end portions, one of said end portions cooperating with said first arcuate portion and the other of said end portions cooperating with said second arcuate portion, rotary movement of said shaft from said neutral position to said actuating positions producing corresponding movement of said over-travel collar, said torsion spring and said actuating collar, and rotary movement of said shaft beyond said actuating positions producing relative movement between said over-travel collar and said actuating collar against the resistance of said torsion spring.

'5. In a mechanism of the character set forth in claim 4, in combination, each of said longitudinally extending arcuate portions being concentric with said control shaft and having substantially the same central angle.

6. In a switch actuating mechanism, in combination, a control shaft rotatable in a clockwise direction from a neutral position to and beyond a first switch actuating position and in a counterclockwise direction from said neutral position to and beyond a second switch actuating position, centering means cooperating with said control shaft for resiliently biasing the same toward said neutral position, means including an actuating collar movably supported on said shaft, an over-travel collar affixed to said shaft, and means for transmitting motion between said over-travel collar and said actuating collar, said lastmen-tioned means including a torsion spring disposed about said shaft'and having two end portions cooperating with said collars, rotary movement of said shaft against the resilient bias of said centering means from said neutral position to said actuating positions producing corresponding movement of said over-travel collar, said t-orsion spring and said actuating collar, and rotary movement of said shaft beyond said actuating positions producing relative movement between said over-travel collar and said actuating colla-r against the resistance of said torsion spring.

7. In a switch actuating mechanism, in combination, a control shaft movable in a clockwise direction from a neutral position to and beyond a first switch actuating position and in a counterclockwise direction from said neutral position to and beyond a second switch actuating position, centering means including a first torsion spring cooperating with said shaft for resiliently biasing the same toward said neutral position, a switch actuating element movable with respect to said shaft, and over-travel means for transmitting motion between said control shaft and said switch actuating element against the resilient bias of said centering means, said over-travel means including a second torsion spring cooperating with said shaft and having two end portions, one of said end portions being movable with said shaft and the other of said end portions controlling said switch actuating element, rotary movement of said shaft to said actuating positions producing corresponding movement of said second torsion spring and said switch actuating element against the resistance of said first torsion spring, and rotary movement of said shaft beyond said actuating positions producing relative movement between said shaft and said switch actuating element against the resistance of said second torsion spring.

'8. A switch actuating mechanism comprising, in combination, a housing for the actuating mechanism, a control shaft movably supported by said housing for clockwise and counterclockwise rotation fro-m a neutral position toward, away from and beyond predetermined actuation points, a switch actuating element supported by said control shaft for rotary movement with respect thereto, over-travel means including a torsion spring interposed between said switch actuating element and said control shaft for transmitting motion therebetween, said torsion spring resiliently resisting clockwise .and counterclockwise rotation of said control shaft beyond said predetermined actuation points, and center-ing means cooperating with said control shaft for resiliently biasing the same toward said neutral position.

9. A switch actuating mechanism comprising, in combination, a housing for the actuating mechanism, a rotary shaft movably supported by said housing for clockwise and counterclockwise rotation from a neutral position toward, away from and beyond predetermined actuation points, means including a switch actuating collar supported by said shaft for rotatry movement with respect thereto, an over-travel collar fixedly mounted on said shaft, means including a torsion spring interposed between said switch actuating collar and said over-travel collar, said torsion spring resiliently resisting clockwise and counterclockwise rotation of said shaft beyond said predetermined actuation points, and centering means oooperating with said shaft for resiliently biasing the same toward said neutral position.

10. A switch actuating mechanism comprising, in combination, a housing for the actuating mechanism, a control shaft movably supported by said housing for clockwise and counterclockwise rotation from a neutral position toward, away from and beyond predetermined actuation points, means including a switch actuating collar supported by said shaft for rotary movement with respect thereto, an over-travel collar fixedly mounted on said shaft, means including a torsion spring interposed between said switch actuating collar and said over-travel collar for transmitting motion therebetween, said torsion spring resiliently resisting clockwise and counterclockwise rotation of said shaft beyond said predetermined actuation points, stop means mounted on said housing in position to engage said over-travel collar for limiting the travel of said shaft, and means including a centering spring cooperating with said shaft for resiliently biasing the same'toward said neutral position.

11. A switch actuating mechanism comprising, in combination, a housing for the actuating mechanism, a rotary shaft movably supported by said housing for clockwise and counterclockwise rotation from a neutral position toward, away from and beyond predetermined actuation points, means including a switch actuating collar supported by said shaft for rotary movement with respect thereto, an over-travel collar fixedly mounted on said shaft, means including a -first torsion spring interposed between said switch actuating collar and said over-travel collar for transmitting motion therebetween, said first torsion spring resiliently resisting clockwise and counterclockwise rotation of said shaft beyond said predetermined actuation points, a centering c-ollsar affixed to said shaft, and means including a second torsion spring acting on said housing and on said centering collar for resiliently biasing said shaft toward said neutral position,

12. A switch actuating mechanism comprising in combination, a housing for the actuating mechanism, a control shaft movably supported by said housing for clockwise and counterclockwise rotation from a neutral position toward, away from and beyond predetermined actuation points, means including an actuating collar rotatably carried by said shaft and having a first longitudinally extending arcuate portion, an over-travel collar affixed to said shaft and having a second longitudinally extending arcuate portion, means including a first torsion spring interposed between said first and second arcuate portions, said first torsion spring resiliently resisting clockwise and counterclockwise rotation of said shaft beyond said predetermined actuation points, a centering collar afiixed to said shaft, and means including a second torsion Spring acting on said housing and on said centering collar for resiliently biasing said shaft toward said neutral position.

13. A switch actuating mechanism comprising, in combination, a housing for the actuating mechanism, a control shaft movably supported by said housing for clock wise and counterclockwise rotation from a neutral position toward, away from and beyond predetermined actuation points, means including an actuating collar rotatably carried by said shaft and having a first longitudinally extending arcuate portion, an over-travel collar afiixed to said shaft and having a second longitudinally extending arcuate portion, means including a first torsion spring interposed between said first and second arcuate portions for transmitting motion between said switch actuating collar and said over-travel collar, said first torsion spring resiliently resisting clockwise andcounterclockwise rotation of said shaft beyond said predetermined actuation points, a centering collar atfixed to said shaft, a reference collar disposed about said shaft in fixed relationship with said housing and means including a second torsion spring acting on said reference collar and on said centering collar for resiliently biasing said shaft toward said neutral position.

14. A switch actuating mechanism of the character set forth in claim 13, in which said centering collar and said reference collar respectively include a third longitudinally extending arcuate portion and a fourth longitudinally ex tending arcuate portion, said second torsion spring having two end portions in position to engage said third and fourth arcuate portions to resiliently bias said centering collar into alignment with said reference collar.

15. A switch actuating mechanism of the character set forth in claim 14, in which said first and second longitudinally extending arcuate portions have substantially the same central angle, and in which said third and fourth longitudinally extending arcuate portions have substantially the same central angle.

16. A switch actuating mechanism comprising, a housing for the actuating mechanism, a control shaft movably supported by said housing for clockwise and counterclockwise rotation from a neutral position toward, away from and beyond predetermined actuation points, an auxiliary shaft carried by said housing in parallel relationship with said control shaft, a switch blade supported on said auxiliary shaft for limited rotary movement with respect thereto, means including an actuating collar rotatably disposed about said control shaft and having a first longitudinally extending arcuate portion, said lastmentioned including means mounted on said actuating collar and engageable with opposite sides of said switch blade for producing said limited rotary movement, an over-travel collar affixed to said control shaft and having a second longitudinally extending arcuate portion, means including a first torsion spring interposed between said first and second arcuate portions for transmitting motion between said switch actuating collar and said over-travel collar, said first torsion spring resiliently resisting clockwise and counterclockwise rotation of said control shaft beyond said predetermined actuation points, a centering collar aflixed to said shaft, and means including a second torsion spring acting on said housing and on said centering collar for resiliently biasing said shaft toward said neutral position.

References Cited by the Examiner UNITED STATES PATENTS 1,480,276 1/ 24 Leake. 2,542,088 2/51 Krieger 200-10 X 2,669,611 2/54 Silvius 2004 BERNARD A. GILHEANY, Primary Examiner. 

1. IN A SWITCH ACTUATING MECHANISM, IN COMBINATION, A CONTROL SHAFT ROTATABLE FROM A NEUTRAL POSITION TO AND BEYOND A SWITCH ACTUATING POSITION, CENTERING MEANS COOPERATING WITH SAID CONTROL SHAFT FOR RESILIENTLY BIASING THE SAME TOWARD SAID NEUTRAL POSITION, A SWITCH ACTUATING ELEMENT MOVABLE WITH RESPECT TO SAID SHAFT, AND OVER-TRAVEL MEANS INCLUDING A TORSION SPRING DISPOSED ABOUT SAID SHAFT AND HAVING TWO END PORTIONS FOR TRANSMITTING MOTION BETWEEN SAID SHAFT AND SAID SWITCH ACTUATING ELEMENT, ONE OF SAID END PORTIONS BEING MOVABLE WITH SAID SHAFT AND THE OTHER OF SAID END PORTIONS CONTROLLING SAID SWITCH ACTUATING ELEMENT, ROTARY MOVEMENT OF SAID SHAFT FROM SAID NEUTRAL POSITION BEYOND SAID SWITCH ACTUATING POSITION BEING RESISTED BY SAID TORSION SPRING. 